Arrangement for an inlet pipe in a rotating drum sieve

ABSTRACT

The present invention relates to an arrangement for an inlet pipe in a rotating drum sieve for the supply of sludge or a liquid mixed with particles to the inside of the rotating drum sieve, which drum sieve exhibits flow openings along its casing, in order to permit the separation of fluid from the sludge, etc., supplied to the internal space of the drum via plurality of discharge openings extending along the longitudinal axis of the drum and capable of being accommodated in the internal space of the drum. The invention permits the effective supply of sludge, etc., to the drum sieve in both small and large flows without the risk of blocking the inlet pipe. At least two simultaneously effective discharge openings for the supply of sludge. etc., to the internal space of the drum are situated on levels separate from one another.

The present invention relates to an arrangement for an inlet pipe in arotating drum sieve for the supply of sludge or a liquid mixed withparticles to the inside of the rotating drum sieve, which drum sieveexhibits flow openings along its casing, in order to permit theseparation of liquid from the sludge, etc., supplied to the internalspace of the drum via a number of discharge openings extending along thelongitudinal axis of the drum and capable of being accommodated in theinternal space of the drum, in conjunction with which the inlet pipeexhibits at least two discharge openings situated on levels separatefrom one another for the purpose of supplying sludge, etc., to theinternal space of the drum.

Inlet pipes of the kind indicated above function excellently with regardto their high capacity for the sludge, etc., supplied. In the case ofsmall flows, however, a plug of screenings can form inside the pipe,which plug is not washed away by small flows, unlike in the case ofmedium or maximum flows. This means that the liquid present in thesludge, etc., strikes the plug which has formed inside the inlet pipeand is discharged through any spillway which may be provided in the drumsieve plant.

Plug formation inside the pipe has caused liquid to flow at aconcentrated rate out towards the sieve casing, with the result that thescreenings have been less well drained, or, in other words, the sievehas not achieved its indicated capacity under conditions of peak load.

Screenings find their way into the sieve casing as the drum rotates, anddrop down into the inlet pipe. These screenings then slide along theinlet pipe, and it is possible to demonstrate that they have droppeddown into the spillway at a number of installations, due to theinclination of the pipe and the sieve.

In the case of sieves which are connected to an inlet box, the liquidremains in the pipe up to a level of half its diameter. This is of noconsequence to the pipe, although it does create problems in connectionwith any work which requires to be carried out on the inlet box, sincequite a considerable quantity of water is left in the bottom.

The principal object of the present invention is thus, in the firstplace, to make available an arrangement which solves said problems insuch a way that one and the same inlet pipe is able to cope with allkinds of flow from 0 up to the maximum throughput of the sieve, with allthe problems previously caused by the screenings removed by sieving.

Said object is achieved by means of an arrangement in accordance withthe present invention, which is characterized essentially in that theinlet pipe is freely open towards the top along said discharge openings,at least to the level of the discharge opening situated in a higherposition.

The invention is described below as a preferred illustrative embodimentof an arrangement for an inlet pipe, in conjunction with which referenceis made to the drawings, in which:

FIG. 1 shows in perspective an inlet arrangement arranged in accordancewith the present invention, viewed at an angle from the front;

FIG. 2 shows a sectioned view of the arrangement;

FIG. 3 shows the arrangement in its operative position with a smallflow;

FIG. 4 shows the arrangement in its operative position with a largeflow;

FIG. 5 shows the arrangement in schematic form installed in a drumsieve;

FIG. 5A shows the arrangement from above;

FIG. 6 is a section along line VI--VI in FIG. 5A;

FIG. 7 is a section along line VII--VII in FIG. 5A;

FIG. 8 is a section along line VIII--VIII in FIG. 5A;

FIG. 9 is a section along line IX--IX in FIG. 5A.

An arrangement 1 for an inlet pipe 2 arranged in accordance with thepresent invention, which inlet pipe is suited to the supply of sludge 3or a similar liquid mixed with particles to the inside 4 of a rotatablydriven drum sieve 5, which along its casing 5A exhibits appropriatepassageways 6 to permit the flow of sieved liquid 7 from the inside 4 ofthe drum, for the purpose of enabling effective separation of the liquid7 from any screenings which are present to be achieved, which screeningscan be discharged via an opening 8 at the end 5B of the drum, comprisesa number of discharge openings 10, 11, 12, 13, extending along thelongitudinal axis 9 of the drum and capable of being accommodated in theinternal space 4 of the drum. These discharge openings 10-13 in theinlet pipe 2 are so arranged as to supply fluid sludge, etc., 3 in aneffective manner via the inlet pipe 2 to the inside 4 of the drum alongthe internal surface 5A of its casing.

In accordance with the invention at least two simultaneously operatingdischarge openings 10, 12 and 11, 13 are situated on levels 14, 15separate from one another for the purpose of supplying sludge, etc., 3to the internal space 4 of the drum.

The discharge openings 10, 12 situated at a lower level 14 are soarranged as to be capable in the lateral sense of the pipe of acceptingthe whole of the flow below a rate of approximately 10 l/sec, ofeffectively feeding the sludge 3 along the extent of the openings inquestion, and of permitting the effective drainage of the pipe 2, asshown in FIG. 3.

The discharge openings 11, 13 situated at a higher level 15 are soarranged as to be capable of accepting the whole of the flow exceeding arate of approximately 10 l/sec, so that the sludge 3 can be fedeffectively through the simultaneously operating discharge openings 10,12 and 11, 13 along their respective extents, as shown in FIG. 4.

Arranged at the free end 2A of the inlet pipe is a flow restricterelement 16, more specifically an end wall, attached to a flange 17, 18which divides said discharge openings 10, 12 and 11, 13 one from theother. The end wall 16 exhibits essentially arched cross-sectional formaway from the inside 4 of the inlet pipe, and is at the bottom attachedto the bottom 19 of said inlet pipe, and is at the top attached to aroof 20 extending over the discharge openings 10-13, which roof exhibitsessentially arched cross-sectional form away from the inside 4 of theinlet pipe.

The inlet part 2B of the inlet pipe which extends into the internalspace 4 of the drum appropriately exhibits lower and upper dischargeopenings 10, 11 and 12, 13 arranged in pairs, which openings aresituated directly in line with one another when the inlet pipe 2 is soarranged as to be set to its central pivoted position, in the event ofthe pipe 2 being pivotally arranged in the desired direction of rotation21, 22.

The lower discharge openings 10, 11 in said channel-shaped inlet part 2Bare appropriately slot-shaped and extend through the wall part 2C ofsaid inlet part 2B, in conjunction with which the bottom 19 of saidchannel 2B is transformed into a lower lateral flow flange 24, 25extending radially and along each lower opening 10, 11.

Upper openings 12, 13 are in turn restricted in a downward sense by saidupper lateral flow flanges 17, 18, which extend radially and along eachpreferably slot-shaped upper opening 12, 13 and are attached to theelement 16, which flanges appropriately extend radially further out inthe lateral sense than the extent to which said lower lateral flowflanges 24, 25 extend radially in the lateral sense.

Said upper lateral flow flanges 17, 18 exhibit an essentially planeextent and extend preferably from the upper part 26 of the channel.

As will be appreciated from the drawings, the lower and upper dischargeopenings 10, 11 and 12, 13, which are preferably situated in pairs,exhibit different lengths viewed in the longitudinal sense of the inletpipe, as a result of the two lower discharge openings 10, 11 starting acertain distance 27 inwards along the channel-shaped part 2B of theinlet pipe 2, thereby exhibiting a shorter longitudinal extent than theother discharge openings 12, 13.

The roof 20 is provided first and foremost for the purpose of protectingthe inlet pipe 2 from falling screenings which may be scraped from theupper internal casing of the drum by means of a conveyor screw 28operating in the internal space 4 of the drum along the surface 5A ofits casing, and which would otherwise present the risk of dropping downand causing problems at the spillway and its associated sensor. On theother hand the roof 20 also produces a damming effect on the flow of thearriving sludge, etc., 3, should this exceed approximately 70 l/sec, forexample. In the event of large flows of approximately 90-100 l/sec, thesludge, etc., 3, is discharged for the most part through the upperdischarge openings 12, 13 in a direction of movement towards thescreening discharge opening 8 situated at the end 5B of the drum. Thismay involve the entire drum 5 wishing to move in said direction. Inorder to counteract this force, which arises with large flows, thesludge, etc., 3 is forced upwards towards the roof 20, which ispreferably executed as a sheet, and is caused by this to traveldownwards towards the channel part 2B, and is thus also discharged viathe lower openings 10, 11. A part of the arriving flow is imparted inthis way with a counter-acting force, which, together with the angle ofupward slope V of the drum, which may be of the order of approximately6°, is sufficient for the drum 5 to rotate against its associated axialroll.

Arranged at the rear end 2C of the inlet pipe are reverse-flowprotectors 29, which prevent the return flow of the sludge, etc., 3outside the pipe 2.

The function of the invention should have emerged clearly from the abovedescription, with reference to the drawings, although it may be statedbriefly that, when the flow is small, the sludge, etc., 3 flows out inthe direction of the arrows A through the lower openings 10, 11,whereas, when the flow is large, the sludge 3 also flows out in thedirection of the arrows B through the upper openings 12, 13.

The invention is not restricted to the illustrative embodiment describedabove and illustrated in the drawings, but may be modified within thescope of the Patent Claims without departing from the idea of invention.

We claim:
 1. Arrangement for an inlet pipe in a rotating drum sieve forsupplying sludge or other liquid/solid mixtures to the inside of a drumsieve, comprising a drum sieve, a casing around said drum sieve, saidcasing having flow openings disposed along its length, an inlet pipehaving at least one lower discharge opening and at least one upperdischarge opening extending in the direction of the longitudinal axis ofsaid drum sieve, said openings being accommodated in an internal volumeof said drum sieve, said inlet pipe having an open area extending alongeach of said upper and lower discharge openings, said open top areaupwardly extending at least to a location vertically even with said atleast one upper discharge opening, a flow restrictor element disposed ata distal end of said inlet pipe, and a flange dividing said at least oneupper discharge opening from said at least one lower discharge opening,said flow restrictor element being attached to said flange. 2.Arrangement according to claim 1, further comprising a roof attached tosaid flow restrictor element, said roof extending above said at leastone upper discharge opening.
 3. Arrangement according to claim 2,wherein said roof is arched.
 4. Arrangement according to claim 3,further comprising a channel shaped inlet element, and an anterior endwall part disposed at a proximal end of said inlet pipe, said channelshaped inlet element extending through said anterior end wall part. 5.Arrangement according to claim 3, wherein said upper and said lowerdischarge openings are arranged in pairs disposed vertically in linewith each other.
 6. Arrangement according to claim 2, further comprisinga channel shaped inlet element, and an anterior end wall part disposedat a proximal end of said inlet pipe, said channel shaped inlet elementextending through said anterior end wall part.
 7. Arrangement accordingto claim 2, wherein said upper and said lower discharge openings arearranged in pairs disposed vertically in line with each other. 8.Arrangement according to claim 1, further comprising a channel shapedinlet element, and an anterior end wall part disposed at a proximal endof said inlet pipe, said channel shaped inlet element extending throughsaid anterior end wall part.
 9. Arrangement according to claim 1,wherein said upper and said lower discharge openings are arranged inpairs disposed vertically in line with each other.
 10. Arrangement foran inlet pipe in a rotating drum sieve for supplying sludge or otherliquid/solid mixtures to the inside of a drum sieve, comprising a drumsieve, a casing around said drum sieve, said casing having flow openingsdisposed along its length, an inlet pipe having at least one lowerdischarge opening and at least one upper discharge opening extending inthe direction of the longitudinal axis of said drum sieve, said openingsbeing accommodated in an internal volume of said drum sieve, said inletpipe having an open area extending along each of said upper and lowerdischarge openings, said open top area upwardly extending at least to alocation vertically even with said at least one upper discharge opening,a channel shaped inlet element, an anterior end wall part disposed at aproximal end of said inlet pipe, said channel shaped inlet elementextending through said anterior end wall part, and a radially extendinglower lateral flow flange disposed near a bottom section of said channelshaped inlet element.
 11. Arrangement according to claim 10, furthercomprising an upper lateral flow flange extending laterally beyond saidlower lateral flow flange.
 12. Arrangement according to claim 11,wherein said upper lateral flow flange extends in a planar directionfrom an upper section of said channel shaped inlet element. 13.Arrangement according to claim 10, further comprising a radiallyextending upper lateral flow flange, wherein said upper lateral flowflange restricts flow through said at least one upper discharge opening.14. Arrangement according to claim 10, wherein said upper and said lowerdischarge openings are arranged in pairs disposed vertically in linewith each other.
 15. Arrangement for an inlet pipe in a rotating drumsieve for supplying sludge or other liquid/solid mixtures to the insideof a drum sieve, comprising a drum sieve, a casing around said drumsieve, said casing having flow openings disposed along its length, aninlet pipe having at least one lower discharge opening and at least oneupper discharge opening extending in the direction of the longitudinalaxis of said drum sieve, said openings being accommodated in an internalvolume of said drum sieve, said inlet pipe having an open area extendingalong each of said upper and lower discharge openings, said open toparea upwardly extending at least to a location vertically even with saidat least one upper discharge opening, wherein said upper and said lowerdischarge openings are arranged in pairs disposed vertically in linewith each other.
 16. Arrangement for an inlet pipe in a rotating drumsieve for supplying sludge or other liquid/solid mixtures to the insideof a drum sieve, comprising a drum sieve, a casing around said drumsieve, said casing having flow openings disposed along its length, aninlet pipe having at least one lower discharge opening and at least oneupper discharge opening extending in the direction of the longitudinalaxis of said drum sieve, said openings being accommodated in an internalvolume of said drum 8 sieve, said inlet pipe having an open areaextending along each of said upper and lower discharge openings, saidopen top area upwardly extending at least to a location vertically evenwith said at least one upper discharge opening, a channel shaped inletelement, an anterior end wall part disposed at a proximal end of saidinlet pipe, said channel shaped inlet element extending through saidanterior end wall part, wherein said upper and said lower dischargeopenings are arranged in pairs disposed vertically in line with eachother.
 17. Arrangement for an inlet pipe in a rotating drum sieve forsupplying sludge or other liquid/solid mixtures to the inside of a drumsieve, comprising a drum sieve, a casing around said drum sieve, saidcasing having flow openings disposed along its length, an inlet pipehaving at least one lower discharge opening and at least one upperdischarge opening extending in the direction of the longitudinal axis ofsaid drum sieve, said openings being accommodated in an internal volumeof said drum sieve, said inlet pipe having an open area extending alongeach of said upper and lower discharge openings, said open top areaupwardly extending at least to a location vertically even with said atleast one upper discharge opening, a channel shaped inlet element, ananterior end wall part disposed at a proximal end of said inlet pipe,said channel shaped inlet element extending through said anterior endwall part, and a radially extending upper lateral flow flange, saidupper lateral flange arranged and constructed to restrict flow throughsaid upper discharge opening, wherein said upper and said lowerdischarge openings are arranged in pairs disposed vertically in linewith each other.